Endoscopic Hemostasis in Porcine Gastrointestinal Tract Using CO2 Low-Temperature Plasma Jet

Recently, atmospheric low-temperature plasma (LTP) has attracted attention as a novel medical tool that might be useful for achieving hemostasis. However, conventional plasma sources are too big for use with endoscopes, and the efficacy of LTP for achieving hemostasis in cases of gastrointestinal bleeding is difficult to investigate. In this study, to solve the problem, we developed a 3D-printed LTP jet that has a diameter of 2.8 mm and metal body for endoscopic use. The characteristics, hemostasis efficacy, and safety were investigated. On investigating the basic characteristics of the developed plasma jet, the electron densities, gas temperatures, and reactive species were measured by emission spectroscopy and thermocouple. To evaluate the efficacy of such hemostatic treatment, porcine gastrointestinal bleeding was treated with the device. In addition, to investigate the safety of such treatment, the CO2 LTP-treated tissue was compared with tissue that was treated with clipping-based or argon plasma coagulation–based hemostasis for 5 d, and hematoxylin and eosin staining was used to evaluate tissue damage in the treated regions. The measurement of emission spectroscopy, power, and electron density of various gas plasmas suggested that a high-density (1014 cm−3) LTP of CO2 was generated by the LTP jet, and the gas temperature was 41.5°C at 3 mm from the outlet of the LTP jet. The CO2 LTP achieved hemostasis of oozing blood by 70 ± 20 s. In addition, the CO2 LTP resulted in earlier recovery than clipping-based or argon plasma coagulation–based hemostases, and the treated regions had no damage by the CO2 LTP treatment. These results indicated that the developed LTP plasma jet has the potential to be used for endoscopic hemostasis.